Added support for mounting EmptyDir volume type (#1679)

* Added emptyDir support for volume mount

* Moved detailed emptyDir configuration spec to --volume

* Added unit tests

* Added readonly false for emptyDir volume

docs/cmd/kn_container_add.md

@@ -38,7 +38,7 @@ kn container add NAME
   -h, --help                         help for add
       --image string                 Image to run.
       --limit strings                The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
-      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -p, --port string                  The port where application listens on, in the format 'NAME:PORT', where 'NAME' is optional. Examples: '--port h2c:8080' , '--port 8080'.
       --pull-policy string           Image pull policy. Valid values (case insensitive): Always | Never | IfNotPresent
       --pull-secret string           Image pull secret to set. An empty argument ("") clears the pull secret. The referenced secret must exist in the service's namespace.

docs/cmd/kn_service_apply.md

@@ -50,7 +50,7 @@ kn service apply s0 --filename my-svc.yml
       --label-service stringArray         Service label to set. name=value; you may provide this flag any number of times to set multiple labels. To unset, specify the label name followed by a "-" (e.g., name-). This flag takes precedence over the "label" flag.
       --limit strings                     The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
       --lock-to-digest                    Keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision) (default true)
-      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -n, --namespace string                  Specify the namespace to operate in.
       --no-cluster-local                  Do not specify that the service be private. (--no-cluster-local will make the service publicly available) (default true)
       --no-lock-to-digest                 Do not keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision)
@@ -71,7 +71,7 @@ kn service apply s0 --filename my-svc.yml
       --service-account string            Service account name to set. An empty argument ("") clears the service account. The referenced service account must exist in the service's namespace.
       --timeout int                       Duration in seconds that the request routing layer will wait for a request delivered to a container to begin replying (default 300)
       --user int                          The user ID to run the container (e.g., 1001).
-      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
+      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or an EmptyDir (prefix ed: or emptyDir:). Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
       --wait                              Wait for 'service apply' operation to be completed. (default true)
       --wait-timeout int                  Seconds to wait before giving up on waiting for service to be ready. (default 600)
       --wait-window int                   Seconds to wait for service to be ready after a false ready condition is returned (default 2)

docs/cmd/kn_service_create.md

@@ -75,7 +75,7 @@ kn service create NAME --image IMAGE
       --label-service stringArray         Service label to set. name=value; you may provide this flag any number of times to set multiple labels. To unset, specify the label name followed by a "-" (e.g., name-). This flag takes precedence over the "label" flag.
       --limit strings                     The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
       --lock-to-digest                    Keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision) (default true)
-      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -n, --namespace string                  Specify the namespace to operate in.
       --no-cluster-local                  Do not specify that the service be private. (--no-cluster-local will make the service publicly available) (default true)
       --no-lock-to-digest                 Do not keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision)
@@ -98,7 +98,7 @@ kn service create NAME --image IMAGE
       --target string                     Work on local directory instead of a remote cluster (experimental)
       --timeout int                       Duration in seconds that the request routing layer will wait for a request delivered to a container to begin replying (default 300)
       --user int                          The user ID to run the container (e.g., 1001).
-      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
+      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or an EmptyDir (prefix ed: or emptyDir:). Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
       --wait                              Wait for 'service create' operation to be completed. (default true)
       --wait-timeout int                  Seconds to wait before giving up on waiting for service to be ready. (default 600)
       --wait-window int                   Seconds to wait for service to be ready after a false ready condition is returned (default 2)

docs/cmd/kn_service_update.md

@@ -62,7 +62,7 @@ kn service update NAME
       --label-service stringArray         Service label to set. name=value; you may provide this flag any number of times to set multiple labels. To unset, specify the label name followed by a "-" (e.g., name-). This flag takes precedence over the "label" flag.
       --limit strings                     The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
       --lock-to-digest                    Keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision) (default true)
-      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray                 Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -n, --namespace string                  Specify the namespace to operate in.
       --no-cluster-local                  Do not specify that the service be private. (--no-cluster-local will make the service publicly available) (default true)
       --no-lock-to-digest                 Do not keep the running image for the service constant when not explicitly specifying the image. (--no-lock-to-digest pulls the image tag afresh with each new revision)
@@ -87,7 +87,7 @@ kn service update NAME
       --traffic strings                   Set traffic distribution (format: --traffic revisionRef=percent) where revisionRef can be a revision or a tag or '@latest' string representing latest ready revision. This flag can be given multiple times with percent summing up to 100%.
       --untag strings                     Untag revision (format: --untag tagName). This flag can be specified multiple times.
       --user int                          The user ID to run the container (e.g., 1001).
-      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
+      --volume stringArray                Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or an EmptyDir (prefix ed: or emptyDir:). Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
       --wait                              Wait for 'service update' operation to be completed. (default true)
       --wait-timeout int                  Seconds to wait before giving up on waiting for service to be ready. (default 600)
       --wait-window int                   Seconds to wait for service to be ready after a false ready condition is returned (default 2)

docs/cmd/kn_source_container_create.md

@@ -27,7 +27,7 @@ kn source container create NAME --image IMAGE --sink SINK
   -h, --help                         help for create
       --image string                 Image to run.
       --limit strings                The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
-      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -n, --namespace string             Specify the namespace to operate in.
   -p, --port string                  The port where application listens on, in the format 'NAME:PORT', where 'NAME' is optional. Examples: '--port h2c:8080' , '--port 8080'.
       --pull-policy string           Image pull policy. Valid values (case insensitive): Always | Never | IfNotPresent
@@ -36,7 +36,7 @@ kn source container create NAME --image IMAGE --sink SINK
       --service-account string       Service account name to set. An empty argument ("") clears the service account. The referenced service account must exist in the service's namespace.
   -s, --sink string                  Addressable sink for events. You can specify a broker, channel, Knative service or URI. Examples: '--sink broker:nest' for a broker 'nest', '--sink channel:pipe' for a channel 'pipe', '--sink ksvc:mysvc:mynamespace' for a Knative service 'mysvc' in another namespace 'mynamespace', '--sink https://event.receiver.uri' for an URI with an 'http://' or 'https://' schema, '--sink ksvc:receiver' or simply '--sink receiver' for a Knative service 'receiver' in the current namespace. If a prefix is not provided, it is considered as a Knative service in the current namespace. If referring to a Knative service in another namespace, 'ksvc:name:namespace' combination must be provided explicitly.
       --user int                     The user ID to run the container (e.g., 1001).
-      --volume stringArray           Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
+      --volume stringArray           Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or an EmptyDir (prefix ed: or emptyDir:). Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
 ```
 
 ### Options inherited from parent commands

docs/cmd/kn_source_container_update.md

@@ -27,7 +27,7 @@ kn source container update NAME --image IMAGE
   -h, --help                         help for update
       --image string                 Image to run.
       --limit strings                The resource requirement limits for this Service. For example, 'cpu=100m,memory=256Mi'. You can use this flag multiple times. To unset a resource limit, append "-" to the resource name, e.g. '--limit memory-'.
-      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
+      --mount stringArray            Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)or an existing Volume (without any prefix) on the specified directory. Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is automatically generated. You can specify a volume subpath by following the volume name with slash separated path. Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. You can use this flag multiple times. For unmounting a directory, append "-", e.g. --mount /mydir-, which also removes any auto-generated volume.
   -n, --namespace string             Specify the namespace to operate in.
   -p, --port string                  The port where application listens on, in the format 'NAME:PORT', where 'NAME' is optional. Examples: '--port h2c:8080' , '--port 8080'.
       --pull-policy string           Image pull policy. Valid values (case insensitive): Always | Never | IfNotPresent
@@ -36,7 +36,7 @@ kn source container update NAME --image IMAGE
       --service-account string       Service account name to set. An empty argument ("") clears the service account. The referenced service account must exist in the service's namespace.
   -s, --sink string                  Addressable sink for events. You can specify a broker, channel, Knative service or URI. Examples: '--sink broker:nest' for a broker 'nest', '--sink channel:pipe' for a channel 'pipe', '--sink ksvc:mysvc:mynamespace' for a Knative service 'mysvc' in another namespace 'mynamespace', '--sink https://event.receiver.uri' for an URI with an 'http://' or 'https://' schema, '--sink ksvc:receiver' or simply '--sink receiver' for a Knative service 'receiver' in the current namespace. If a prefix is not provided, it is considered as a Knative service in the current namespace. If referring to a Knative service in another namespace, 'ksvc:name:namespace' combination must be provided explicitly.
       --user int                     The user ID to run the container (e.g., 1001).
-      --volume stringArray           Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
+      --volume stringArray           Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or an EmptyDir (prefix ed: or emptyDir:). Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. You can use this flag multiple times. To unset a ConfigMap/Secret reference, append "-" to the name, e.g. --volume myvolume-.
 ```
 
 ### Options inherited from parent commands

pkg/kn/flags/podspec.go

@@ -137,18 +137,20 @@ func (p *PodSpecFlags) AddFlags(flagset *pflag.FlagSet) []string {
 	flagNames = append(flagNames, "env-file")
 
 	flagset.StringArrayVarP(&p.Mount, "mount", "", []string{},
-		"Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), or an existing Volume (without any prefix) on the specified directory. "+
+		"Mount a ConfigMap (prefix cm: or config-map:), a Secret (prefix secret: or sc:), an EmptyDir (prefix ed: or emptyDir:)"+
-			"Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, or --mount /mydir=myvolume. "+
+			"or an existing Volume (without any prefix) on the specified directory. "+
-			"When a configmap or a secret is specified, a corresponding volume is automatically generated. "+
+			"Example: --mount /mydir=cm:myconfigmap, --mount /mydir=secret:mysecret, --mount /mydir=emptyDir:myvol "+
-			"You can specify a volume subpath by following the volume name with slash separated path. "+
+			"or --mount /mydir=myvolume. When a configmap or a secret is specified, a corresponding volume is "+
+			"automatically generated. You can specify a volume subpath by following the volume name with slash separated path. "+
 			"Example: --mount /mydir=cm:myconfigmap/subpath/to/be/mounted. "+
 			"You can use this flag multiple times. "+
 			"For unmounting a directory, append \"-\", e.g. --mount /mydir-, which also removes any auto-generated volume.")
 	flagNames = append(flagNames, "mount")
 
 	flagset.StringArrayVarP(&p.Volume, "volume", "", []string{},
-		"Add a volume from a ConfigMap (prefix cm: or config-map:) or a Secret (prefix secret: or sc:). "+
+		"Add a volume from a ConfigMap (prefix cm: or config-map:) a Secret (prefix secret: or sc:), or "+
-			"Example: --volume myvolume=cm:myconfigmap or --volume myvolume=secret:mysecret. "+
+			"an EmptyDir (prefix ed: or emptyDir:). "+
+			"Example: --volume myvolume=cm:myconfigmap, --volume myvolume=secret:mysecret or --volume emptyDir:myvol:size=1Gi,type=Memory. "+
 			"You can use this flag multiple times. "+
 			"To unset a ConfigMap/Secret reference, append \"-\" to the name, e.g. --volume myvolume-.")
 	flagNames = append(flagNames, "volume")

pkg/kn/flags/podspec_helper.go

@@ -20,6 +20,7 @@ import (
 	"strconv"
 	"strings"
 
+	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/util/yaml"
 
 	corev1 "k8s.io/api/core/v1"
@@ -35,6 +36,7 @@ type VolumeSourceType int
 const (
 	ConfigMapVolumeSourceType VolumeSourceType = iota
 	SecretVolumeSourceType
+	EmptyDirVolumeSourceType
 	PortFormatErr = "the port specification '%s' is not valid. Please provide in the format 'NAME:PORT', where 'NAME' is optional. Examples: '--port h2c:8080' , '--port 8080'."
 )
 
@@ -466,6 +468,8 @@ func updateVolume(volume *corev1.Volume, info *volumeSourceInfo) error {
 	case SecretVolumeSourceType:
 		volume.ConfigMap = nil
 		volume.Secret = &corev1.SecretVolumeSource{SecretName: info.volumeSourceName}
+	case EmptyDirVolumeSourceType:
+		volume.EmptyDir = &corev1.EmptyDirVolumeSource{Medium: corev1.StorageMedium(info.emptyDirMemoryType), SizeLimit: info.emptyDirSize}
 	default:
 		return fmt.Errorf("Invalid VolumeSourceType")
 	}
@@ -486,8 +490,7 @@ func updateVolumeMountsFromMap(volumeMounts []corev1.VolumeMount, toUpdate *util
 			if !existsVolumeNameInVolumes(name, volumes) {
 				return nil, fmt.Errorf("There is no volume matched with %q", name)
 			}
-
+			volumeMount.ReadOnly = isReadOnlyVolume(name, volumes)
-			volumeMount.ReadOnly = true
 			volumeMount.Name = name
 			volumeMount.SubPath = volumeMountInfo.SubPath
 			set[volumeMount.MountPath] = true
@@ -501,7 +504,7 @@ func updateVolumeMountsFromMap(volumeMounts []corev1.VolumeMount, toUpdate *util
 		if !set[mountPath] {
 			volumeMounts = append(volumeMounts, corev1.VolumeMount{
 				Name:      name,
-				ReadOnly:  true,
+				ReadOnly:  isReadOnlyVolume(name, volumes),
 				MountPath: mountPath,
 				SubPath:   volumeMountInfo.SubPath,
 			})
@@ -579,38 +582,65 @@ func removeVolumes(volumes []corev1.Volume, toRemove []string, volumeMounts []co
 // =======================================================================================
 
 type volumeSourceInfo struct {
-	volumeSourceType VolumeSourceType
+	volumeSourceType   VolumeSourceType
-	volumeSourceName string
+	volumeSourceName   string
+	emptyDirMemoryType string
+	emptyDirSize       *resource.Quantity
 }
 
 func newVolumeSourceInfoWithSpecString(spec string) (*volumeSourceInfo, error) {
-	slices := strings.SplitN(spec, ":", 2)
+	slices := strings.SplitN(spec, ":", 3)
-	if len(slices) != 2 {
+	if len(slices) < 2 {
-		return nil, fmt.Errorf("argument requires a value that contains the : character; got %q", spec)
+		return nil, fmt.Errorf("argument requires a value that contains the : character; got %q, %q", spec, slices)
 	}
 
-	var volumeSourceType VolumeSourceType
+	if len(slices) == 2 {
+		var volumeSourceType VolumeSourceType
 
-	typeString := strings.TrimSpace(slices[0])
+		typeString := strings.TrimSpace(slices[0])
-	volumeSourceName := strings.TrimSpace(slices[1])
+		volumeSourceName := strings.TrimSpace(slices[1])
+
+		switch typeString {
+		case "config-map", "cm":
+			volumeSourceType = ConfigMapVolumeSourceType
+		case "secret", "sc":
+			volumeSourceType = SecretVolumeSourceType
+		case "emptyDir", "ed":
+			volumeSourceType = EmptyDirVolumeSourceType
+		default:
+			return nil, fmt.Errorf("unsupported volume source type \"%q\"; supported volume source types are \"config-map\" and \"secret\"", slices[0])
+		}
+
+		if len(volumeSourceName) == 0 {
+			return nil, fmt.Errorf("the name of %s cannot be an empty string", volumeSourceType)
+		}
+
+		return &volumeSourceInfo{
+			volumeSourceType: volumeSourceType,
+			volumeSourceName: volumeSourceName,
+		}, nil
+	} else {
+		typeString := strings.TrimSpace(slices[0])
+		switch typeString {
+		case "config-map", "cm", "secret", "sc":
+			return nil, fmt.Errorf("incorrect mount details for type %q", typeString)
+		case "emptyDir", "ed":
+			volName := slices[1]
+			edType, edSize, err := getEmptyDirTypeAndSize(slices[2])
+			if err != nil {
+				return nil, err
+			}
+			return &volumeSourceInfo{
+				volumeSourceType:   EmptyDirVolumeSourceType,
+				volumeSourceName:   volName,
+				emptyDirMemoryType: edType,
+				emptyDirSize:       edSize,
+			}, nil
+		default:
+			return nil, fmt.Errorf("unsupported volume type \"%q\"; supported volume types are \"config-map or cm\", \"secret or sc\", \"volume or vo\", and \"emptyDir or ed\"", slices[0])
+		}
 
-	switch typeString {
-	case "config-map", "cm":
-		volumeSourceType = ConfigMapVolumeSourceType
-	case "secret", "sc":
-		volumeSourceType = SecretVolumeSourceType
-	default:
-		return nil, fmt.Errorf("unsupported volume source type \"%q\"; supported volume source types are \"config-map\" and \"secret\"", slices[0])
 	}
-
-	if len(volumeSourceName) == 0 {
-		return nil, fmt.Errorf("the name of %s cannot be an empty string", volumeSourceType)
-	}
-
-	return &volumeSourceInfo{
-		volumeSourceType: volumeSourceType,
-		volumeSourceName: volumeSourceName,
-	}, nil
 }
 
 func (vol *volumeSourceInfo) getCanonicalName() string {
@@ -649,6 +679,15 @@ func (vol *volumeSourceInfo) createEnvFromSource() *corev1.EnvFromSource {
 
 // =======================================================================================
 
+func isReadOnlyVolume(volumeName string, volumes []corev1.Volume) bool {
+	for _, volume := range volumes {
+		if volume.Name == volumeName {
+			return volume.EmptyDir == nil
+		}
+	}
+	return true
+}
+
 func existsVolumeNameInVolumes(volumeName string, volumes []corev1.Volume) bool {
 	for _, volume := range volumes {
 		if volume.Name == volumeName {
@@ -714,9 +753,18 @@ func reviseVolumeInfoAndMountsToUpdate(mountsToUpdate *util.OrderedMap, volumesT
 				})
 				mountInfo.VolumeName = generatedName
 				mountsToUpdateRevised.Set(path, mountInfo)
-
+			case "emptyDir", "ed":
+				generatedName := util.GenerateVolumeName(path)
+				mountInfo := getMountInfo(slices[1])
+				volumeSourceInfoByName.Set(generatedName, &volumeSourceInfo{
+					volumeSourceType:   EmptyDirVolumeSourceType,
+					volumeSourceName:   slices[1],
+					emptyDirMemoryType: "",
+				})
+				mountInfo.VolumeName = generatedName
+				mountsToUpdateRevised.Set(path, mountInfo)
 			default:
-				return nil, nil, fmt.Errorf("unsupported volume type \"%q\"; supported volume types are \"config-map or cm\", \"secret or sc\", and \"volume or vo\"", slices[0])
+				return nil, nil, fmt.Errorf("unsupported volume type \"%q\"; supported volume types are \"config-map or cm\", \"secret or sc\", \"volume or vo\", and \"emptyDir or ed\"", slices[0])
 			}
 		}
 	}
@@ -733,6 +781,61 @@ func reviseVolumeInfoAndMountsToUpdate(mountsToUpdate *util.OrderedMap, volumesT
 	return volumeSourceInfoByName, mountsToUpdateRevised, nil
 }
 
+func getEmptyDirTypeAndSize(value string) (string, *resource.Quantity, error) {
+	slices := strings.SplitN(value, ",", 2)
+	formatErr := fmt.Errorf("incorrect format to specify emptyDir type")
+	repeatErrStr := "cannot repeat the key %q"
+	var dirType string
+	var size *resource.Quantity
+	switch len(slices) {
+	case 0:
+		return "", nil, nil
+	case 1:
+		typeSizeSlices := strings.SplitN(slices[0], "=", 2)
+		if len(typeSizeSlices) < 2 {
+			return "", nil, formatErr
+		}
+		switch strings.ToLower(typeSizeSlices[0]) {
+		case "type":
+			dirType = typeSizeSlices[1]
+		case "size":
+			quantity, err := resource.ParseQuantity(typeSizeSlices[1])
+			if err != nil {
+				return "", nil, formatErr
+			}
+			size = &quantity
+		default:
+			return "", nil, formatErr
+		}
+	case 2:
+		for _, slice := range slices {
+			typeSizeSlices := strings.SplitN(slice, "=", 2)
+			if len(typeSizeSlices) < 2 {
+				return "", nil, formatErr
+			}
+			switch strings.ToLower(typeSizeSlices[0]) {
+			case "type":
+				if dirType != "" {
+					return "", nil, fmt.Errorf(repeatErrStr, "type")
+				}
+				dirType = typeSizeSlices[1]
+			case "size":
+				if size != nil {
+					return "", nil, fmt.Errorf(repeatErrStr, "size")
+				}
+				quantity, err := resource.ParseQuantity(typeSizeSlices[1])
+				if err != nil {
+					return "", nil, formatErr
+				}
+				size = &quantity
+			default:
+				return "", nil, formatErr
+			}
+		}
+	}
+	return dirType, size, nil
+}
+
 func reviseVolumesToRemove(volumeMounts []corev1.VolumeMount, volumesToRemove []string, mountsToRemove []string) []string {
 	for _, pathToRemove := range mountsToRemove {
 		for _, volumeMount := range volumeMounts {

pkg/kn/flags/podspec_helper_test.go

@@ -21,8 +21,10 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
+	"k8s.io/apimachinery/pkg/api/resource"
 	"knative.dev/client/lib/test"
 
 	"gotest.tools/v3/assert"
@@ -228,6 +230,7 @@ func TestUpdateEnvFrom(t *testing.T) {
 }
 
 func TestUpdateVolumeMountsAndVolumes(t *testing.T) {
+	quantity := resource.MustParse("10Gi")
 	spec, container := getPodSpec()
 	spec.Volumes = append(spec.Volumes,
 		corev1.Volume{
@@ -255,7 +258,41 @@ func TestUpdateVolumeMountsAndVolumes(t *testing.T) {
 			VolumeSource: corev1.VolumeSource{
 				Secret: &corev1.SecretVolumeSource{
 					SecretName: "existing-secret-2",
-				}}})
+				}}},
+		corev1.Volume{
+			Name: "new-empty-dir-volume-name-1",
+			VolumeSource: corev1.VolumeSource{
+				EmptyDir: &corev1.EmptyDirVolumeSource{
+					Medium:    "",
+					SizeLimit: nil,
+				},
+			},
+		},
+		corev1.Volume{
+			Name: "new-empty-dir-volume-name-2",
+			VolumeSource: corev1.VolumeSource{
+				EmptyDir: &corev1.EmptyDirVolumeSource{
+					Medium:    "Memory",
+					SizeLimit: &quantity,
+				},
+			},
+		},
+		corev1.Volume{
+			Name: "new-empty-dir-volume-name-3",
+			VolumeSource: corev1.VolumeSource{
+				EmptyDir: &corev1.EmptyDirVolumeSource{
+					Medium: "Memory",
+				},
+			},
+		},
+		corev1.Volume{
+			Name: "new-empty-dir-volume-name-4",
+			VolumeSource: corev1.VolumeSource{
+				EmptyDir: &corev1.EmptyDirVolumeSource{
+					SizeLimit: &quantity,
+				},
+			},
+		})
 
 	container.VolumeMounts = append(container.VolumeMounts,
 		corev1.VolumeMount{
@@ -278,6 +315,31 @@ func TestUpdateVolumeMountsAndVolumes(t *testing.T) {
 			ReadOnly:  true,
 			MountPath: "/existing-secret-2/mount/path",
 		},
+		corev1.VolumeMount{
+			Name:      "new-empty-dir-volume-name-1",
+			ReadOnly:  false,
+			MountPath: "/empty-dir-1/mount/path",
+		},
+		corev1.VolumeMount{
+			Name:      "new-empty-dir-volume-name-2",
+			ReadOnly:  false,
+			MountPath: "/empty-dir-2/mount/path",
+		},
+		corev1.VolumeMount{
+			Name:      "new-empty-dir-volume-name-3",
+			ReadOnly:  false,
+			MountPath: "/empty-dir-3/mount/path",
+		},
+		corev1.VolumeMount{
+			Name:      "new-empty-dir-volume-name-4",
+			ReadOnly:  false,
+			MountPath: "/empty-dir-4/mount/path",
+		},
+		corev1.VolumeMount{
+			Name:      "new-empty-dir-volume-name-5",
+			ReadOnly:  false,
+			MountPath: "/empty-dir-5/mount/path",
+		},
 	)
 
 	err := UpdateVolumeMountsAndVolumes(spec,
@@ -310,29 +372,87 @@ func TestUpdateVolumeMountsAndVolumes(t *testing.T) {
 			"existing-secret-volume-name-1"})
 	assert.NilError(t, err)
 
-	assert.Equal(t, len(spec.Volumes), 4)
+	err = UpdateVolumeMountsAndVolumes(spec,
-	assert.Equal(t, len(container.VolumeMounts), 6)
+		util.NewOrderedMapWithKVStrings([][]string{{"/empty-dir-1/mount/path", "new-empty-dir-volume-name-1"}}),
+		[]string{},
+		util.NewOrderedMapWithKVStrings([][]string{{"new-empty-dir-volume-name-1", "emptyDir:new-empty-dir-volume-name-1"}}),
+		[]string{})
+	assert.NilError(t, err)
+
+	err = UpdateVolumeMountsAndVolumes(spec,
+		util.NewOrderedMapWithKVStrings([][]string{{"/empty-dir-2/mount/path", "new-empty-dir-volume-name-2"}}),
+		[]string{},
+		util.NewOrderedMapWithKVStrings([][]string{{"new-empty-dir-volume-name-2", "emptyDir:new-empty-dir-volume-name-2:type=Memory,size=10Gi"}}),
+		[]string{})
+	assert.NilError(t, err)
+
+	err = UpdateVolumeMountsAndVolumes(spec,
+		util.NewOrderedMapWithKVStrings([][]string{{"/empty-dir-3/mount/path", "new-empty-dir-volume-name-3"}}),
+		[]string{},
+		util.NewOrderedMapWithKVStrings([][]string{{"new-empty-dir-volume-name-3", "emptyDir:new-empty-dir-volume-name-3:type=Memory"}}),
+		[]string{})
+	assert.NilError(t, err)
+
+	err = UpdateVolumeMountsAndVolumes(spec,
+		util.NewOrderedMapWithKVStrings([][]string{{"/empty-dir-4/mount/path", "new-empty-dir-volume-name-4"}}),
+		[]string{},
+		util.NewOrderedMapWithKVStrings([][]string{{"new-empty-dir-volume-name-4", "emptyDir:new-empty-dir-volume-name-4:size=10Gi"}}),
+		[]string{})
+	assert.NilError(t, err)
+
+	err = UpdateVolumeMountsAndVolumes(spec,
+		util.NewOrderedMapWithKVStrings([][]string{{"/empty-dir-5/mount/path", "emptyDir:new-empty-dir-volume-name-5"}}),
+		[]string{},
+		util.NewOrderedMap(),
+		[]string{})
+	assert.NilError(t, err)
+
+	assert.Equal(t, len(spec.Volumes), 9)
+	assert.Equal(t, len(container.VolumeMounts), 11)
+
 	assert.Equal(t, spec.Volumes[0].Name, "existing-config-map-volume-name-2")
 	assert.Equal(t, spec.Volumes[0].ConfigMap.Name, "updated-config-map")
 	assert.Equal(t, spec.Volumes[1].Name, "existing-secret-volume-name-2")
 	assert.Equal(t, spec.Volumes[1].Secret.SecretName, "updated-secret")
-	assert.Equal(t, spec.Volumes[2].Name, "new-config-map-volume-name")
+	assert.Equal(t, spec.Volumes[2].Name, "new-empty-dir-volume-name-1")
-	assert.Equal(t, spec.Volumes[2].ConfigMap.Name, "new-config-map")
+	assert.Equal(t, spec.Volumes[2].EmptyDir.Medium, corev1.StorageMediumDefault)
-	assert.Equal(t, spec.Volumes[3].Name, "new-secret-volume-name")
+	assert.Assert(t, spec.Volumes[2].EmptyDir.SizeLimit == nil)
-	assert.Equal(t, spec.Volumes[3].Secret.SecretName, "new-secret")
+	assert.Equal(t, spec.Volumes[3].Name, "new-empty-dir-volume-name-2")
+	assert.Equal(t, spec.Volumes[3].EmptyDir.Medium, corev1.StorageMediumMemory)
+	assert.DeepEqual(t, spec.Volumes[3].EmptyDir.SizeLimit, &quantity)
+	assert.Equal(t, spec.Volumes[4].Name, "new-empty-dir-volume-name-3")
+	assert.Equal(t, spec.Volumes[4].EmptyDir.Medium, corev1.StorageMediumMemory)
+	assert.Equal(t, spec.Volumes[5].Name, "new-empty-dir-volume-name-4")
+	assert.DeepEqual(t, spec.Volumes[5].EmptyDir.SizeLimit, &quantity)
+	assert.Equal(t, spec.Volumes[6].Name, "new-config-map-volume-name")
+	assert.Equal(t, spec.Volumes[6].ConfigMap.Name, "new-config-map")
+	assert.Equal(t, spec.Volumes[7].Name, "new-secret-volume-name")
+	assert.Equal(t, spec.Volumes[7].Secret.SecretName, "new-secret")
+	assert.Assert(t, strings.Contains(spec.Volumes[8].Name, "empty-dir-5"))
+	assert.Equal(t, spec.Volumes[8].EmptyDir.Medium, corev1.StorageMediumDefault)
+	assert.Assert(t, spec.Volumes[8].EmptyDir.SizeLimit == nil)
 
 	assert.Equal(t, container.VolumeMounts[0].Name, "existing-config-map-volume-name-2")
 	assert.Equal(t, container.VolumeMounts[0].MountPath, "/existing-config-map-2/mount/path")
 	assert.Equal(t, container.VolumeMounts[1].Name, "existing-secret-volume-name-2")
 	assert.Equal(t, container.VolumeMounts[1].MountPath, "/existing-secret-2/mount/path")
-	assert.Equal(t, container.VolumeMounts[2].Name, "new-config-map-volume-name")
+	assert.Equal(t, container.VolumeMounts[2].Name, "new-empty-dir-volume-name-1")
-	assert.Equal(t, container.VolumeMounts[2].MountPath, "/new-config-map/mount/path")
+	assert.Equal(t, container.VolumeMounts[2].MountPath, "/empty-dir-1/mount/path")
-	assert.Equal(t, container.VolumeMounts[3].Name, "existing-config-map-volume-name-2")
+	assert.Equal(t, container.VolumeMounts[3].Name, "new-empty-dir-volume-name-2")
-	assert.Equal(t, container.VolumeMounts[3].MountPath, "/updated-config-map/mount/path")
+	assert.Equal(t, container.VolumeMounts[3].MountPath, "/empty-dir-2/mount/path")
-	assert.Equal(t, container.VolumeMounts[4].Name, "new-secret-volume-name")
+	assert.Equal(t, container.VolumeMounts[4].Name, "new-empty-dir-volume-name-3")
-	assert.Equal(t, container.VolumeMounts[4].MountPath, "/new-secret/mount/path")
+	assert.Equal(t, container.VolumeMounts[4].MountPath, "/empty-dir-3/mount/path")
-	assert.Equal(t, container.VolumeMounts[5].Name, "existing-secret-volume-name-2")
+	assert.Equal(t, container.VolumeMounts[5].Name, "new-empty-dir-volume-name-4")
-	assert.Equal(t, container.VolumeMounts[5].MountPath, "/updated-secret/mount/path")
+	assert.Equal(t, container.VolumeMounts[5].MountPath, "/empty-dir-4/mount/path")
+	assert.Equal(t, container.VolumeMounts[6].MountPath, "/empty-dir-5/mount/path")
+	assert.Equal(t, container.VolumeMounts[7].Name, "new-config-map-volume-name")
+	assert.Equal(t, container.VolumeMounts[7].MountPath, "/new-config-map/mount/path")
+	assert.Equal(t, container.VolumeMounts[8].Name, "existing-config-map-volume-name-2")
+	assert.Equal(t, container.VolumeMounts[8].MountPath, "/updated-config-map/mount/path")
+	assert.Equal(t, container.VolumeMounts[9].Name, "new-secret-volume-name")
+	assert.Equal(t, container.VolumeMounts[9].MountPath, "/new-secret/mount/path")
+	assert.Equal(t, container.VolumeMounts[10].Name, "existing-secret-volume-name-2")
+	assert.Equal(t, container.VolumeMounts[10].MountPath, "/updated-secret/mount/path")
 }
 
 func TestUpdateContainerImage(t *testing.T) {